Microtubule associated protein (Tau) is found predominantly in the central neural system and its major function is to promote assembly and to stabilize neuronal microtubules. Six isoforms of Tau were identified in humans that are differentiated by the exclusion or inclusion of exons 2, 3, and 10. Tau-441 is the longest of Tau isoforms, consisting of 441 amino acids with molecular mass of 71.8 kDa. Under physiological conditions Tau can undergo abnormal phosphorylation, truncation, or other modifications that result in the protein detachment from microtubules. These modified Tau molecules can self-associate and form different types of aggregates including neurofibrillary tangles (NFTs) found in brains of patients with neurodegenerative diseases such as Alzheimer’s disease.